qcow2 template, clone to LVM - possible?

After some successful cloning processes (LVM template, LVM destination) I'm trying to improve the speed by using compressed qcow2 template instead.
The LVM is 50GB, and the compressed .qcow2 I created is 400MB, so it means essentially I read only 400MB over network (but still write 50GB to destination) instead of reading the full 50GB LVM.

I then tried to place the .qcow2 template in varios places to get proxmox web ui to pick it up, so I can use it from the gui but to no avail. I tried sticking it on both "template" (nfs) datastores and "images" (nfs) datastore, at the following paths:

/mnt/pve/templates/template/centos-minimal-try1.qcow2
/mnt/pve/os-isos/images/centos-minimal-try1.qcow2
/mnt/pve/os-isos/centos-minimal-try1.qcow2
/mnt/pve/os-isos/dump/centos-minimal-try1.qcow2

Proxmox is not picking it up, so I guess the proxmox backends reads the contents of the above directories periodically, but only expects a certain type of file names etc. Please advice!

I generated the the qcow2 file from an existing (LVM) template, using qemu-img like this:

qemu-img convert -t writeback -c -p -O qcow2 /dev/TEST01/vm-103-disk-1 -c /mnt/pve/templates/template/centos-minimal-try1.qcow2


Please advice